Chasing a slightly lumpy idle...still

[Laird Scooby]

As yours is a 1990 car Phil, it only has to meet 3.5%CO and <= 1200ppm HC and doesn't need a cat. It would have to be one fussy article of an MoT tester to try and fail it because you've gutted it.

As you rightly point out, you've got something like a 20% increase in economy so you're using 20% less fuel and 20% less money each week to fund it.
You also get the benefits of a smoother, more responsive engine and i suspect (especially as you've renewed the Lambda sensor) you'll find the emissions are pretty low come MoT time and regardless of all else, your car should qualify for the "BET" which is also the same as above (3.5%CO etc) even if they try and say the cat isn't working.

Given the improvements you've got, i expect it will pass even the cat emissions test though. I forgot one year to refit the cat on my Sterling and it passed emissions but he had to fail it on the lack of cat (mine is 1994 but with the cat is eligible for the BET because it's before a certain VIN - go figure!!! ) which was quite ironic as the emissions went UP once i refitted the cat! Still within limits but shows how much the damned things choke the engine!

[Stephen Edwin]

AllHailKingVolvo. Life does become controversial. It all comes out in the wash.

For myself, I just remain cautious about: to keep the cat or to de cat that is the question.

As I contributed earlier approx. I don't pretend to understand the complexities.

There are not two sides to such issues. There are many facets. Deep joy.

Your position approx. that fuel economy saves more emissions than cat is on the same line as my argument that low mileage &c. reduces emissions.


.

[AllHailKingVolvo]

Just an update...I treated my 744 to a new Coolant Temperature Sensor for Christmas (well, an early present, fitted it today!) as it was misfiring very slightly under load up steep hills, and I suspected overfuelling when hot.

Sensor went in with zero drama, and what a difference! The car pulls like a train now, up hill and down dale, with zero misfires whatsoever. Hurrah!

[Stephen Edwin]

Originally Posted by AllHailKingVolvo

Just an update...I treated my 744 to a new Coolant Temperature Sensor for Christmas (well, an early present, fitted it today!) as it was misfiring very slightly under load up steep hills, and I suspected overfuelling when hot.

Sensor went in with zero drama, and what a difference! The car pulls like a train now, up hill and down dale, with zero misfires whatsoever. Hurrah!

Having graduated on the A Series. The trouble with subsequent early modern engines is, so many components that must have a shelf life.

Plain speaking. Where is the actual get from A to B advantage of subsequent engines ?????

I am pleased to hear of your success.



Like a train? Not with leaves on the line???


.

[Laird Scooby]

Originally Posted by AllHailKingVolvo

Just an update...I treated my 744 to a new Coolant Temperature Sensor for Christmas (well, an early present, fitted it today!) as it was misfiring very slightly under load up steep hills, and I suspected overfuelling when hot.

Sensor went in with zero drama, and what a difference! The car pulls like a train now, up hill and down dale, with zero misfires whatsoever. Hurrah!

Would that be the Bosch sensor Phil as advised elsewhere by (i think) LPTJoe?

I fitteed an Intermotor one to mine (it's one of the few parts shared with the red block) and just lately, it's been giving a slightly uneven idle, slight missing under load unless cold, i knnow it dropped the CO content considerably so i tweaked the pot on the MAF, slight but no real improvement. Seriously thinking i need to go down the Bosch sensor route.